A petroleum brownfield is a property on which expansion, redevelopment, or reuse may be complicated by the presence, or perceived presence, of petroleum contamination. Petroleum contamination can be found at many different types of properties. Many abandoned sites, such as old gas stations, auto service businesses, factories, mill sites, shipyards, transit stations, and junkyards have been found to be contaminated by petroleum. A property that is perceived to be contaminated by petroleum is a potential petroleum brownfield site until assessment of the site proves there is no petroleum contamination or clearly identifies contaminants of concern so they can be cleaned up to meet the designated end use.

The size of petroleum brownfield sites varies significantly; some sites are smaller than an acre, while other sites are huge former industrial properties. Some petroleum sites are bare soil, while others have existing buildings and infrastructure. Some sites have been assessed while others have not; some properties have been assessed and also cleaned up while others have not. For redevelopment purposes, it is important to remember that small sites can be combined to make larger sites if that is what is needed.

It is not hard to locate petroleum brownfield sites. Sometimes it is as simple as driving past and taking note of an old abandoned gas station and then checking with your state regulatory authority for information on the site. Many states and local governments have lists (often called inventories or databases) on their web pages of brownfield properties, including petroleum sites, within their jurisdictions. EPA encourages states and local areas to develop and maintain lists or inventories of brownfield properties that could potentially be reused. The EPA Office of Underground Storage Tanks has developed a petroleum brownfields inventory development guide titled Petroleum Brownfields: Developing Inventories that a state or local area can use to create or enhance an inventory of sites. Your state regulatory authority or state brownfields program is the best place to find a listing of brownfield sites.

Below are just a few examples of the lists (often called inventories or databases) of brownfield sites compiled by specific states. While some states have a separate list for petroleum-contaminated sites, states often include the petroleum sites in a more comprehensive inventory of all brownfield sites within the state. State and local officials use these inventories to promote the availability and marketability of their petroleum brownfield sites. Developers and others use the lists to look for potential reuse sites.

Some state lists contain only addresses of petroleum sites while others contain detailed information on each property, including its former use, lot size, buildings, and infrastructure. Some state websites include maps of brownfields sites. Some databases of sites are searchable. States can use EPA's Petroleum Brownfields: Developing Inventories to create or enhance their inventories of sites.